PETROLEUM REFINERYCENTRIFUGAL GAS COMPRESSOR VARNISH REMOVAL & HVOF

By Larry B. Jordan, Sr. Technical Advisor, RIG Case Study

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SYNOPSISRIG successfully removed varnish from a refinery’s centrifu-gal compressor lube oil system, achieving changing the MPC from >40 to 1. High velocity flushing combined with side streaming filtration an chemical cleaning.

GLOBAL LEADERSIN PRECOMMISSION &PLANT MAINTENANCE

3” 150# Suction on The Reservoir Prior to Flushing

INTRODUCTIONIn addition to a high level of wear metal contam-ination the refinery’s centrifugal compressors lubricant was showing MPC values >40 which put it in a critical level for varnish potential.

Figure 1. Evaluation

RIG was contracted to provide services on the compres-sor lube oil system during the turnaround. The services performed included:

• Varnish mitigation flush with Step One Cleaner• Purge / particle contamination flush with virgin oil• Side stream filtration of final fill oil

OPERATIONSPrior to arriving on site RIG personnel completed all site specific safety training requirements. RIG personnel and equipment arrived onsite on the scheduled date to start. Once checked-in with contact, permitting require-ments were completed and the flushing equipment was staged in the dedicated location near the lube oil reservoir.

The system spools were removed in preparation of installation of the RIG supplied flushing jumpers. Ad-ditionally RIG personnel made connections from the flushing equipment to the compressor lube oil system.

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Supply to the flushing skid was pulled from the lube oil reservoir. Figures 2, 3, & 4 show various items from the lube oil system prior to flushing and cleaning.

The varnish removal flush began by circulating and heating the existing oil using the RIG flushing pump and heater. Once the oil reached 150⁰F the system cleaner was added at %5 blend to the system. This started the 72-hour varnish mitigation flush. RIG technicians cycled all the bypass circuits and alternated flow between the oil coolers and filter housings during the flush.

At the end of the 72 hours, RIG immediately drained the reservoir and all low point drains as quickly as possible. The system was thoroughly blown down with plant nitrogen.

The door on the oil reservoir was removed to gain access to the interior for cleaning. Large amounts of debris ranging from paint chips to varnish and sludge were found in the reservoir. Confined space entry was

Figure 2. Interior of the Oil Reservoir Prior to Cleaning and Flushing

Figure 3. 3”150# Suction On the Reservoir Prior to Flushing

Figure 4. Sight Glass Removed for Hand Cleaning

Figure 5. Gearbox and Compressor Jumpers

Figure 6. Debris in the Oil Reser-voir After the Varnish Mitigation Flush

Figure 7. Oil Reservoir After Cleaning Post Varnish Mitigation Flush

not allowed at this facility, so the reservoir was cleaned from the outside with squeegees and shop vacuums. The final reservoir cleanliness was inspected and approved by the customer representative.

After the reservoir was inspected and covers reinstat-ed, the system was filled with virgin oil. The purge and particulate flush was started. This stage removed any residual system cleaner from the oil system and was used for inspections for particulate contamination. Initial inspection screens became plugged with debris after an hour of flushing. (See Figure 8)

A course flush was executed without inspection screens installed for 12 hours. After 12 hours, a subsequent one-hour screening run showed improvement. The flush continued with RIG technicians alternating flow through the oil coolers and filter housings every hour.

During the flushing sequence, the final fill oil was being filtered in a storage tote with a 1-micron filter. This insured the final fill oil met the ISO code specifications when the purge/particulate flush was completed.

Figure 8. Initial Inspection Screens Check After 1-Hour Flushing

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Figure 9. Final Inspec-tion Screen Check

Figure 10. Field Particle Analysis Results for Purge Oil

Figure 11. Field Par-ticle Analysis Results for Final Fill

Inspection screen runs were performed until a one-hour run produced clean screens. A confirmation screen one-hour run was performed to confirm the pipe cleanliness. Final inspection screens are shown in Figure 8. The purge oil was field tested for particle count and returned an ISO code of 15/14/10. The final fill oil was also tested and returned an ISO code particle count of 16/14/11. The test results for the field particle counter are shown in Figures 10 & 11.

The customer approved the inspection screen and ISO cleanliness of the system. RIG shut down the flushing equipment, closed all valves, and began reinstating the system. The final fill oil was filter filled into the oil reservoir.

A sample from both the final purge oil and a from the final fill oil were sent to a third-party lab for final par-ticle count and MPC analysis. The lab results showed final particle count for the purge oil was 16/14/11 and 15/14/10 for the final fill oil. MPC on the final oil was re-ported at a color value of 1. Final laboratory test reports are shown in Appendices I, II & III.

CONCLUSIONRIG safely completed the varnish mitigation flush, purge/particulate flush, and filter fill on the centrifugal compressor lube oil system. The job was able to suc-cessfully remove varnish from, and MPC >40 to 1, in the lube oil system. System cleanliness was verified by API 614 specifications by producing clean inspection screen after a 1-hour run followed by another successful confirmation run. The final fill oil had a final ISO code particle count of 16/14/11 from the field particle counter and 15/14/10 from laboratory confirmation testing.

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Appendix I: Purge Oil – Post Flush Analysis Results

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Appendix II: Final Fill Oil – Post Filtering Oil Analysis Results

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Appendix III: Post MPC Test (After 3 Months)

Contact us for more information:

info@therigteam.com800-770-4510 (Domestic)+1 281-339-5751 (International)www.TheRigTeam.com

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